Transfer of Transgenic Protein Products across a graft union to no-transgenic scions
The application of transformation technology to grapes is usually envisioned as requiring
the transformation of each cultivar of interest. But this need not be the case if a
transgenic plant can be united by grafting with an important variety, and if the transgene
product can be mobilized across the graft union. The present project seeks to test how
best to move substances across graft unions via phloem tissues. Previous work with
tobacco and Arabidopsis has demonstrated that gene products can be mobilized into the
phloem and can move across a graft union. But the method for doing so has not been
optimized, nor has this technique been tested in a woody perennial like the grapevine.
Several transformation cassettes have been constructed for use in transforming tobacco
and Vitis vinifera tissues and testing whether transgenic proteins can move throughout the
vine via phloem transport. Four different constructs have been used to transform Vitis
vinifera tissues (via the “gene gun” technique), which are currently on selective media.
There are imminent plans to introduce the same four constructs into tobacco tissues,
again through the use of the gene gun. Experiments with tobacco, a model plant for us
that grows easily and rapidly, will help to inform the experiments that will follow with
grapevines. Work continues in regard to generating seven additional transformation
cassettes and introducing them into both tobacco and ?Chardonnay?.